A method and system for evaluating carbon sink and storage capacity of forestry carbon sink based on coupling of forest land and forest product whole industry chain

Abstract

The application discloses a kind of comprehensive evaluation methods of coupling forestry carbon sink carbon storage capacity of forest land-forest product whole industry chain, on the basis of process-based ecosystem model, coupling forest product carbon storage accounting model, through the model of coupling, can simulate different climate conditions, different rotation period, different soil conditions, timber production of forest land, carbon sequestration capacity and carbon storage capacity of forest products after felling, comprehensive evaluation forest land-forest product whole industry chain carbon sink carbon storage.This application has the following advantages: first, based on climate-driven forest ecosystem process simulates the carbon cycle of forest ecosystem (vegetation and soil) under different management conditions (rotation period);Second, the coupling of natural and social systems whole industry chain carbon cycle is realized;Third, the carbon sink carbon storage capacity and carbon assets of forestry whole industry chain can be comprehensively evaluated.

Description

Technical Field

[0001] This invention belongs to the field of forestry technology, and in particular relates to a method and system for assessing forestry carbon sink and carbon storage capacity that couples the entire industrial chain of forest land and forest products. Background Technology

[0002] Enhancing forestry carbon sequestration capacity is a crucial measure to address global warming. This is primarily achieved by improving forest stand structure, leveraging the carbon sequestration function of plantation forests without sacrificing the industrial value of timber production, thereby increasing net ecosystem productivity. After logging, it is generally believed that the carbon from harvested forest products is directly returned to the atmosphere.

[0003] The carbon sink and storage capacity of existing forests can be quantified at different temporal and spatial scales using process-based ecosystem models. Most forest ecosystem process models, when used to simulate and predict carbon storage in mature forests, generally only consider undisturbed, mature, and similarly aged forests, rarely taking into account the impacts of forest management practices such as logging on the ecosystem. The Intergovernmental Panel on Climate Change (IPCC) currently recommends using the production approach to account for the carbon storage of forest products derived from sustainable forest management in each country, applying the basic principles of product life cycle assessment to calculate forest product carbon storage at national and regional scales. However, product life cycle assessment emphasizes a comprehensive evaluation of the environmental impact of a product throughout its entire life cycle, from raw material acquisition to final disposal, assessing the environmental impact of material and energy inputs and outputs within the system boundaries. Due to the unique nature of forest products, forest land carbon budgets are typically not considered; therefore, the carbon storage accounting and turnover issues of forest products are separated.

[0004] In reality, carbon from forest products circulates within the social system, and the carbon cycles of forest land and forest products are interconnected. However, current research on quantifying carbon storage or carbon sequestration remains independent and fragmented. Therefore, accurately assessing the carbon sequestration and storage capacity of the entire forestry industry chain, including forest land and forest products, is a crucial step in enhancing forestry's carbon sequestration and storage capacity.

[0005] Therefore, a new method is urgently needed to accurately assess the carbon sink and storage capacity of the entire forestry industry chain, from forest land to forest products. Summary of the Invention

[0006] Purpose of the invention: This invention aims to propose a method and system for assessing forestry carbon sink and carbon storage capacity that couples the entire industrial chain of forest land and forest products, so as to more comprehensively assess forestry carbon sink and carbon storage capacity and carbon assets.

[0007] Technical solution:

[0008] This invention proposes a method for assessing forestry carbon sink and carbon storage capacity that couples the entire forest land and forest product industrial chain, including:

[0009] S1: Collect initial information of the target forest land, set the range of tree species growth parameters, and obtain the input parameters of the process-based ecosystem process model; initialize the ecosystem process model according to the input parameters, set the rotation period, simulate forest stand growth, and calculate the annual forest land carbon storage change and the forest land carbon storage of the target forest land within a specified period.

[0010] S2: Construct a forest product carbon storage accounting model based on the IPCC first-order decay method to calculate the annual forest product carbon storage change of the target forest land and the forest product carbon storage of the target forest land within a specified period.

[0011] S3: Couple the output of the ecosystem process model with the input of the forest product carbon storage accounting model to obtain a coupled model; the coupled model stores the biomass carbon after each rotation period as forest land carbon storage, and the forest land carbon storage is gradually returned to the atmosphere through the half-life of forest products;

[0012] S4: Calculate the forestry carbon storage of the target forest land within a specified period using the coupling model, wherein the forestry carbon storage is coupled with the carbon storage of the forest land and the carbon storage of the forest products; analyze the carbon flow path and carbon budget change process of the target forest land, and calculate the carbon assets of the target forest land to assess the forestry carbon sink and carbon storage capacity of the target forest land.

[0013] Furthermore, the initial information of the target forest land includes meteorological data, soil physicochemical data, and vegetation data. The range of tree species growth parameters is set according to expert experience, including stand density, tree height, and tree shape.

[0014] Furthermore, the forest carbon storage includes standing tree biomass and soil organic carbon.

[0015] Furthermore, the forest product carbon storage accounting model includes:

[0016] The annual carbon storage of the biomass carbon of the growing forest stand, the annual carbon storage of the in-use forest product carbon pool, and the annual carbon storage of the abandoned forest product carbon pool in the target forest land are calculated separately, and the sum of the three is obtained to obtain the annual forest product carbon storage.

[0017] Based on the initial carbon storage of forest products in the target forest land, the annual carbon storage of forest products in the target forest land is calculated by adding the annual carbon storage of forest products in the harvesting year according to the rotation period.

[0018] The change in forest product carbon storage is obtained by subtracting the annual forest product carbon storage from the annual carbon storage of two adjacent years.

[0019] Furthermore, the annual carbon storage of the waste forest product carbon pool is calculated using the method specified by the IPCC.

[0020] Furthermore, the carbon flow pathways of the target forest land being analyzed include:

[0021] The commercially available timber volume output from the ecosystem process model is used as forest land carbon storage, and is allocated to solid forest products and paper forest products in the forest product carbon storage accounting model according to a certain proportion.

[0022] Several simulation scenarios were set up, each including the corresponding planting density and rotation period; carbon flow paths were simulated with reference to the LCA life cycle assessment.

[0023] Furthermore, the analysis of the carbon budget changes in the target forest land includes:

[0024] The carbon budget of the target forest land is based on a specified year. The forestry net carbon balance is obtained from the coupled forest land-forest product net carbon balance obtained from the coupled model, and is expressed as:

[0025]

[0026] In the formula For a specified year Forestry net carbon balance, The first result obtained from the ecosystem process model Annual change in carbon storage. The carbon emissions from the waste forest product carbon pool in the forest product carbon storage accounting model are estimated in the form of methane.

[0027] Furthermore, the carbon asset accounting includes:

[0028] Convert flux to carbon dioxide equivalent units , will specify the year Carbon market prices and forestry net carbon balance Multiplying these values ​​yields the carbon asset value of the target forest land.

[0029] On the other hand, this invention also proposes a forestry carbon sink capacity assessment system that couples a process model with carbon budget, comprising:

[0030] The data initialization module is used to collect initial information about the target forest land, set the range of tree species growth parameters, and obtain the input parameters of the process-based ecosystem process model; the ecosystem process model is initialized according to the input parameters, and the rotation period is set.

[0031] Ecosystem process models are used to simulate stand growth and calculate the annual changes in forest carbon storage and the forest carbon storage of the target forest over a specified period.

[0032] The forest product carbon storage accounting model is constructed based on the IPCC first-order decay method and is used to calculate the annual change in forest product carbon storage of the target forest land and the forest product carbon storage of the target forest land within a specified period.

[0033] The coupling module is used to couple the output of the ecosystem process model with the input of the forest product carbon storage accounting model to obtain a coupled model. The coupled model stores the biomass carbon after each rotation period as forest land carbon storage, and the forest land carbon storage is gradually returned to the atmosphere through the half-life of forest products.

[0034] The analysis module is used to calculate the forestry carbon storage of the target forest land within a specified period using the coupled model, wherein the forestry carbon storage is coupled with the carbon storage of the forest land and the carbon storage of the forest products; analyze the carbon flow path and carbon budget change process of the target forest land, and perform carbon asset calculation on the target forest land to assess the forestry carbon sink and carbon storage capacity of the target forest land.

[0035] On the other hand, the present invention also proposes a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the aforementioned methods.

[0036] Beneficial effects:

[0037] This invention improves upon traditional process-based ecosystem models, specifically the TRIPLEX-Management model, by coupling a forest product carbon storage accounting model. This coupled model enables comprehensive accounting and evaluation of forest / forest land-forest product carbon storage at the stand scale. The carbon storage calculation in the forest product carbon storage accounting model is primarily based on an improved IPCC first-order decay model. The commercially viable timber volume output from the TRIPLEX-Management model is used as the forest land carbon storage, and the carbon storage transferred to the forest product module is automatically and comprehensively simulated and evaluated at the stand scale without requiring separate, precise data.

[0038] This invention is applicable to the calculation of forest product carbon storage in other types of forest farms. Because the process-based ecosystem model input module is adjustable, only the input data needs to be modified to make it suitable for calculating forest / forest land carbon storage in various forest farms.

[0039] This invention comprehensively considers forest carbon balance and accounting for forest product carbon storage, as well as carbon emissions throughout the life cycle of forest products. By optimizing and analyzing physiological and ecological parameters and conducting sensitivity analysis, it improves the model's simulation accuracy of carbon cycling in mixed forests, achieves a comprehensive assessment of forestry carbon sink capacity, helps to more accurately predict the impact of different management measures on forest carbon storage, and provides more reliable data support for forest management decisions. Attached Figure Description

[0040] Figure 1 This is a flowchart of the method of the present invention;

[0041] Figure 2 This is a framework diagram of the coupling model of the present invention;

[0042] Figure 3 This is a graph showing the change in carbon storage of forest products in use in this embodiment;

[0043] Figure 4 This is a graph showing the cumulative carbon storage changes of forest products (in use and waste) in this embodiment.

[0044] Figure 5 This is a graph showing the change in cumulative carbon storage between forest land and forest products in this embodiment.

[0045] Figure 6 This is a graph showing the change in ecosystem carbon flux in this embodiment;

[0046] Figure 7 This is a graph showing the change in carbon assets in the forestry carbon pool in this embodiment. Detailed Implementation

[0047] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0048] like Figure 1 The diagram shows a flowchart of a forestry carbon sink and carbon storage capacity assessment method that couples the entire forest land and forest product industry chain according to the present invention, which specifically includes the following steps:

[0049] S1: Collect initial information on the target forest land, set the range of tree species growth parameters, and obtain the input parameters for the ecosystem process model (TRIPLEX-Management model); initialize the ecosystem process model based on the input parameters, set the rotation period, simulate stand growth, and calculate the annual forest land carbon storage change and the forest land carbon storage of the target forest land within a specified period. The forest land carbon storage is the biomass carbon of the forest land, which is represented in the form of commercially available timber volume in this invention.

[0050] The initial information includes meteorological, soil physicochemical properties, and initial vegetation information. Based on expert experience, the range of tree species growth parameters (including Alpha C, Max height, Crown / DBH, Min / Max h / d, C density, etc.) is set to complete the configuration of the TRIPLEX-Management model input parameters. The required parameters are detailed in Table 1.

[0051] Table 1 Parameters of the TRIPLEX-Management Model

[0052] parameter describe Absorb Atmospheric absorption factor Cloud The proportion of cloudy days PAR factor Solar radiation factor BlCond <![CDATA[Canopy boundary layer conductance (ml m −2 s −1 )]]> MaxCond <![CDATA[Maximum canopy conductance (ml m −2 s −1 )]]> StomCond <![CDATA[Stomatal conductance (ml m −2 s −1 )]]> ExtCoef Radiative extinction coefficient TaMin Minimum growth temperature (°C) TaMax Maximum growth temperature (°C) Topt Optimal growth temperature (°C) N factor N affects growth factors Na The effect of age on GPP Sla <![CDATA[Specific leaf area (m 2 kg −1 )]]> GamaF Annual blade turnover GamaR Annual fine root turnover Lnr Lignin–N ratio Ls lignin in leaves, fine roots, coarse roots, branches, and wood Ts Sand content Tc Clay content Tsi Particle content A1, A2, A3 Soil water depth (cm) in layers 1, 2, and 3 AWL1, 2, 3 Relative root density of layers 1, 2, and 3 KF The ratio flowing into the river KD Deep water ratio KX The ratio of deep water flowing into rivers AWater Maximum soil moisture content (mm) SWConst Soil moisture constant MiuNorm Normal mortality rate MiuCrowd Competition mortality rate CSP <![CDATA[Carbon density (t C m −3 )]]> CD Crown-to-stem diameter ratio AlphaC Canopy quantum efficiency SOC <![CDATA[Initial soil organic carbon (t ha -1 )]]> Stock <![CDATA[Initial carbon pool (t ha -1 )]]> MaxHeight Maximum tree height (m) AgeMax Maximum age (yr)

[0053] The TRIPLEX-Management model comprises six sub-modules: photosynthetically active radiation, total primary productivity, net primary productivity, forest growth and yield, soil carbon and nitrogen dynamics, and soil water balance. Specifically, it references existing technology (Jiao Wenxing. Simulation of the Influence of Stand Density and Soil Conditions on Carbon Allocation in Populus plantations in northern Jiangsu based on an improved process model [D]. Nanjing Forestry University, 2022.). The TRIPLEX-Management model is used to simulate forest carbon flux and carbon storage, and can output commercially viable timber volume for subsequent steps in the forest product carbon storage accounting model.

[0054] The formula for calculating the commercially viable timber volume in the model is as follows:

[0055]

[0056] In the above formula, Total commercially viable timber volume It is the stand density, which is the number of trees per unit area (trees / hectare). For the height of the tree, The shape factor, For diameter, Let be the diameter distribution function, which describes the probability density of the tree diameter distribution within the forest stand.

[0057] S2: Construct a carbon storage accounting model for forest products based on the IPCC first-order decay method, calculate the annual carbon storage of the in-use woody forest product carbon pool and the annual carbon storage of abandoned forest products respectively, obtain the annual carbon storage change in the target forest land, and calculate the cumulative carbon storage for the specified year by rolling the annual carbon storage change based on the initial year carbon storage data collected from the target forest land.

[0058] The forest product carbon storage accounting model described herein is constructed based on the IPCC first-order decay method, with updated and modified IPCC formulas. It is an independent carbon storage accounting model for woody forest products (Harvest Wood Product, hereinafter referred to as HWP), meeting the research needs of actual forest product lifecycles and sample plot conditions. The HWP carbon storage accounting model used in this invention includes:

[0059] (1) Calculation of annual carbon storage in the HWP carbon pool. The formula is:

[0060]

[0061] In the above formula, i represents the year; Let k be the carbon storage of commodity category l in the HWP pool in year i; k = ln(2) / HL, which is the first-order decay variable of HWP; HL is the half-life of a specific HWP in the HWP pool. The carbon inflow of wood products is allocated to two major carbon pools, one of which is solid wood products ( One is paper and wood products ( The default ratio is 0.6 and 0.4, meaning the carbon inflow into wood products is divided into a 60 / 40 split. The ratio data used in this embodiment is based on the 2023 HWP production of solid wood products and paper-based wood products in China. This data can be modified as needed when analyzing specific forest farms. The half-life (HL) value for solid wood products during the usage phase is 30, and the HL value for paper-based wood products during the usage phase is 2.

[0062] (2) Annual carbon storage calculation of abandoned HWP carbon pools.

[0063] Waste logging products accumulate at solid waste treatment sites, resulting in greenhouse gas emissions or permanent carbon storage, depending on the treatment method. The following formula references and modifies existing research (Xiaobiao Zhang, Hongqiang Yang, Jiaxin Chen. Life-cycle carbon budget of China's harvested woodproducts in 1900–2015[J]. Forest Policy and Economics, 2018, 92: 181–192.), and its principle is the same as the IPCC first-order decay method.

[0064]

[0065] In the above formula, This indicates the amount of carbon that flowed into the forest product carbon pool in the previous year. Indicates in The annual carbon inflow allocated to the waste HWP carbon pool includes two main categories: one is solid wood products. One is paper and wood products. , represented as:

[0066]

[0067] Specifically, this invention calculates the carbon emissions of waste wood products caused by four methods: recycling, incineration, landfill, and open-air storage.

[0068] (2.1) The waste wood products in the recycling section are mainly recycled paper. Assume that all the recycled parts are recycled paper and all come from paper-based wood products. Let the carbon inflow of recycled paper products in year i be denoted as . The formula for calculating the carbon inflow during the recycling phase is as follows:

[0069]

[0070] The amount of recycled paper is reduced from the amount of paper waste in that year. Multiply by dynamic recovery rate The dynamic recycling rate increases year by year, with the recycling rate for large-diameter timber set at 0.10 and the recycling rate for small-diameter timber set at 0.30, an annual growth rate of 0.01, and an upper limit of 0.60, simulating a scenario where the recycling rate increases due to technological advancements and policy influences.

[0071] The formula for calculating the cumulative carbon storage of recycled paper is as follows:

[0072]

[0073] It is obtained by removing the recycled paper portion from waste paper and wood products. This is used for subsequent processing and indicates that waste paper carbon banks are given priority for recycling.

[0074]

[0075] (2.2) After incineration, all wood products are released into the atmosphere as CO2. The resulting carbon emissions are calculated using the following formula:

[0076]

[0077] In the above formula, express Carbon emissions from annual incineration Indicates waste wood products The proportion of carbon emissions from incineration is considered "recyclable carbon emissions," meaning that the CO2 released from incineration comes from the biomass itself and belongs to a short-cycle carbon cycle. The model classifies it as an instantaneous emission and therefore does not include it in the carbon budget calculation.

[0078] (2.3) Landfilling decomposes wood products slowly without oxygen, resulting in the release of a constant amount of greenhouse gases into the atmosphere and permanent carbon sequestration. Open-air storage of waste wood products decomposes slowly, but the decomposition rate differs from that of landfilling, as the presence of oxygen accelerates the decomposition process.

[0079] The formula for calculating carbon reserves resulting from slow, anaerobic decomposition under landfill disposal is as follows:

[0080]

[0081] In the formula, The cumulative carbon storage of the slowly decomposing portion of waste wood forest products disposed of in landfill in year i; In order to be in The proportion of waste wood forest products that are not recycled and disposed of in landfills; The proportion of slow decomposition in the anaerobic decomposition fraction is set to 0.5 (IPCC, 2006a). To indicate the waste wood products in The proportion of landfill disposal per year This indicates the amount of carbon inflow allocated to carbon pools for incineration, landfill, and open-air stockpiling of forest products. Open-air stockpiling treatment. The calculation can be completed by replacing the half-life data. The k-value for landfill disposal of solid wood products is 0.024, the k-value for landfill disposal of paper wood products is 0.046, the k-value for open-air storage disposal of solid wood products is 0.042, and the k-value for open-air storage disposal of paper wood products is 0.084.

[0082] The formula for calculating the cumulative carbon storage of the slowly decomposing portion of waste timber products in the initial year is as follows:

[0083]

[0084] In the above formula It is the initial year's landfill carbon reserves, equal to the carbon flow allocated to the first year. Multiply by the proportion of the initial year of landfilling that flowed into the landfill. And the proportion of slow decomposition in the anaerobic decomposition portion, This represents the proportion of slowly decomposing components within the anaerobic decomposition phase.

[0085] The formula for calculating the carbon storage capacity of the permanent carbon sequestration portion under landfill disposal is as follows:

[0086]

[0087] In the above formula, This represents the cumulative carbon sequestration in waste wood products after landfill disposal in year i.

[0088] In addition to CO2, the greenhouse gases emitted from the anaerobic decomposition portion of products undergoing landfill disposal also include CH4. For the same mass, the greenhouse effect of CH4 is 28 times that of CO2. Therefore, the total carbon emissions from the slow, anaerobic decomposition under landfill disposal are calculated using the following formula:

[0089]

[0090]

[0091] In the above formula, R Land (i) is The total cumulative carbon emissions generated annually from the slow, anaerobic decomposition of waste wood products in landfills. This invention modifies the IPCC formula, as the original formula often overestimates methane emissions. Here, it is assumed that newly added waste in a given year only undergoes a six-month decay period, which is more realistic. This indicates that CH4 emissions are equivalent to 28 times the greenhouse effect of CO2; 0.9 means that 10% of the CH4 produced by the decomposition of waste wood products in landfills is naturally oxidized into CO2 after reaching the top layer of soil.

[0092] (2.4) The calculation for open-air treatment is based on landfill treatment, simply by changing the proportions. Specifically, the landfill carbon storage calculation formula is as follows: The proportion of waste wood products replaced by open-air storage With other parts remaining unchanged, the carbon storage in the open-air stockpile was calculated. .

[0093] In summary, the formula for calculating the annual carbon storage of abandoned HWP carbon pools is as follows:

[0094]

[0095] In the above formula, It is the annual change in carbon storage. For waste wood products Annual carbon storage recovered For waste wood products Carbon storage from the decomposition portion during annual landfill disposal For waste wood products Carbon storage capacity of the permanent carbon sequestration portion under annual landfill disposal. For waste wood products The carbon storage of the aerobic decomposition portion under annual open-air storage treatment, with 27 / 28 being the conversion factor to deduct the greenhouse effect of CH4 equivalent to CO2.

[0096] After calculations in steps (1) to (2) of the independent HWP carbon storage accounting model, the annual carbon storage of in-use forest products and the annual carbon storage of abandoned forest products are obtained.

[0097] First, calculate the annual changes for the two sub-pools in use and those in waste, and add them together to get the total annual change. Then, use this total annual change to accumulate year by year from the base year to obtain the cumulative carbon storage for any given year. Due to the characteristics of methane emissions (methane is considered a "released immediately and not allowed to remain" decomposition product, and the CH4 produced when waste is landfilled / decomposed in the open air will be directly released into the atmosphere instead of remaining in the carbon pool), the calculation of cumulative carbon storage excludes the impact of methane emissions.

[0098] S3: Couple the output of the TRIPLEX-Management model with the input of the HWP carbon storage accounting model to obtain a coupled model; the coupled model uses the biomass carbon after each rotation period as carbon storage, and gradually returns it to the atmosphere through the half-life of forest products, to calculate the forestry carbon storage that couples the forest land carbon storage with the forest product carbon storage.

[0099] This invention uses the input parameters of a forest product carbon storage model constructed based on the IPCC first-order decay method as the main interface, and employs the TRIPLEX-Management model to generate the data required for the forest product carbon model. It enables the analysis of the production lifecycle starting from the volume of commercially available timber. The coupled model framework (including involved parameters, ecological processes, etc.) is as follows: Figure 2 As shown.

[0100] The analysis of the production life cycle begins with the volume of commercially available timber. First, the volume of commercially available timber is converted into carbon stock, which is then allocated to four final disposal categories for HWPs: recycling, landfill, incineration, and open stockpiling. Recycling extends the lifespan and carbon storage of HWPs; landfilling HWPs results in some carbon sequestration and some methane emissions; and incinerating HWPs immediately releases the wood carbon into the atmosphere.

[0101] The formula is used to calculate how much timber is used in the forest product process:

[0102]

[0103] In the above formula, Let the carbon input be the amount of commodity category l in the HWP library for year i. This refers to the volume of commercially viable timber that flows into the forest product carbon pool in the year preceding the rotational logging year. This data comes from the output of the TRIPLEX-Management model. It is the carbon content coefficient of wood. This refers to the forest product conversion rate. In this embodiment, the carbon content coefficient of timber is set to 0.5, and the forest product conversion rate is 0.6. This ratio can be modified according to actual conditions. This formula unifies the output of the TRIPLEX-Management model and the input of the forest product carbon storage accounting model.

[0104] S4: Calculate the forestry carbon storage of the target forest land within a specified period using the coupled model, analyze the carbon budget changes of the target forest land, and calculate the carbon assets of the target forest land to assess its forestry carbon sink and storage capacity. Specifically, the forestry carbon storage is a coupled carbon budget that couples forest land carbon storage with forest product carbon storage.

[0105] The coupled model was used to simulate different silvicultural conditions and rotation periods to calculate the forest's land carbon sequestration (carbon storage) capacity and forest product carbon storage capacity. This embodiment uses a poplar plantation in northern Jiangsu as the research object, and employs the improved TRIPLEX-Management model to simulate the plantation's timber production, carbon sequestration capacity, and forest product carbon storage capacity under different silvicultural conditions and soil conditions.

[0106] The target forest area for this study is located in Sihong Forest Farm on the west bank of Hongze Lake in Suqian City, Jiangsu Province. In 2007, a poplar plantation was established using one-year-old cloned seedlings of "Nanlin 95". This clone was created by hybridizing I-69 (Populus deltoides Bartr. cv. 'Lux') × clone I-45 (P. euramericana Guineir. cv. 'I-45 / 51'), covering an area of ​​approximately 6.7 hectares. The input data for this embodiment mainly comes from existing literature and sample plot survey data. Climate data comes from meteorological data from the China Meteorological Data Service Center (http: / / data.cma.cn / ). Temperature, precipitation, and temperature-humidity data from 1980 to 2019 are included in the dataset. Future data will be simulated by the TRIPLEX-Management model itself.

[0107] This embodiment utilizes sample plot data from existing research to simulate and compare variables such as diameter at breast height (DBH), tree height, aboveground biomass, and belowground biomass in poplar plantations to verify the accuracy of the model simulation. Most general data and non-species or location-specific parameters in the TRIPLEX-Management model are kept unchanged, including parameters such as the conductance to saturated vapor pressure gradient, lignin nitrogen ratio, and radiative extinction coefficient, as shown in Tables 2 and 3. For the northern Jiangsu region, site and stand characteristic data (e.g., environmental or site conditions, stand volume, and tree species growth characteristics) from permanent sample plots in existing studies are used to estimate species-specific and site-specific parameters, and some other parameters are modified during calibration.

[0108] Table 2 Parameters used in model simulation

[0109] parameter describe source Absorb=0.15 Atmospheric absorption factor Bossel et al, 1996 Cloud=0.45 The proportion of cloudy days Jiao Wenxing, 2022 PAR factor=0.65 Solar radiation factor Ryan et al, 1997 BlCond=0.12 <![CDATA[Canopy boundary layer conductance (ml m −2 s −1 )]]> Landsberg et al, 1997 MaxCond=0.26 <![CDATA[Maximum canopy conductance (ml m −2 s −1 )]]> Landsberg et al, 1997 StomCond=0.012 <![CDATA[Stomatal conductance (ml m −2 s −1 )]]> Landsberg et al, 1997 ExtCoef=0.5 Radiative extinction coefficient Coops et al, 2001 TaMin=5 Minimum growth temperature (°C) Jiao Wenxing, 2022 TaMax=40 Maximum growth temperature (°C) Bossel et al, 1996 Topt=15 Optimal growth temperature (°C) Jiao Wenxing, 2022 N factor=0.2 N affects growth factors Parton et al, 1993 Na=4 The effect of age on GPP Jiao Wenxing, 2022 Sla=19 <![CDATA[Specific leaf area (m 2 kg −1 )]]> Jiao Wenxing, 2022 GamaF=1 Annual blade turnover Zhou et al, 2005 GamaR=0.21 Annual fine root turnover Jiao Wenxing, 2022 Lnr=26 Lignin–N ratio Giardina et al, 2001 Ls=0.215,0.215,0.2351,0.255,0.255 lignin in leaves, fine roots, coarse roots, branches, and wood Parton et al, 1993 Ts=0.34 Sand content Jiao Wenxing, 2022 Tc=0.25 Clay content Jiao Wenxing, 2022 Tsi=0.41 Particle content Jiao Wenxing, 2022 A1, A2, A3 = 15, 15, 15 Soil water depth (cm) in layers 1, 2, and 3 Jiao Wenxing, 2022 AWL1, 2, 3 = 0.5, 0.3, 0.2 Relative root density of layers 1, 2, and 3 Parton et al, 1993 KF=0.5 The ratio flowing into the river Zhou et al, 2005 KD=0.5 Deep water ratio Zhou et al, 2005 KX=0.3 The ratio of deep water flowing into rivers Zhou et al, 2005 AWater=250 Maximum soil moisture content (mm) Zhou et al, 2005 SWConst=0.55 Soil moisture constant Jiao Wenxing, 2022 MiuNorm=0 Normal mortality rate Jiao Wenxing, 2022 MiuCrowd=0 Competition mortality rate Jiao Wenxing, 2022 CSP=0.26 <![CDATA[Carbon density (t C m −3 )]]> Jiao Wenxing, 2022 CD=20 Crown-to-stem diameter ratio Bossel et al, 1996 AlphaC=0.08 Canopy quantum efficiency Landsberg et al, 1997 SOC=65 <![CDATA[Initial soil organic carbon (t ha -1 )]]> This embodiment defines Stock=0.6 Initial carbon pool Jiao Wenxing, 2022 MaxHeight=30 Maximum tree height (m) Jiao Wenxing, 2022 AgeMax=30 Maximum age (yr) Jiao Wenxing, 2022

[0110] Table 3 Default Conversion Factors for IPCC HWP Categories

[0111] HWP Category Dry matter density carbon content carbon density Solid wood products <![CDATA[0.5 drying t / m 3 > 0.50 <![CDATA[0.25 drying t / m 3 > Paper and paperboard 0.9 t of drying / t of air drying - 0.386 t / air-dried t Recycled paper 0.9 t of drying / t of air drying - 0.386 t / air-dried t

[0112] In this embodiment, the parameters used in the coupled forest product carbon storage accounting model refer to the parameters recommended by the IPCC and those obtained from surveys. The range of newly generated parameters from model coupling, such as timber yield and forest product grade efficiency, is confirmed.

[0113] Following step S3, the changes in the forestry carbon pool of the target forest land are analyzed, including simulating the forest's timber production, carbon sequestration capacity, and carbon storage capacity of forest products under different silvicultural and soil conditions. Specifically, the analysis process in this embodiment is as follows:

[0114] The baseline scenario was set based on actual information from Sihong Forest Farm, with a density of 600 trees / ha. -1 The rotation period is 20 years. Based on practical considerations, four scenarios were designed: a low-density scenario (density 200 trees / ha). -1 Rotation period of 30 years), low to medium density scenario (density of 400 trees / ha) -1 Rotation period of 25 years), baseline scenario (density of 600 ha -1 Rotation period is 20 years), high-density scenario (density 1000 trees / ha) -1 (The rotation period is 15 years).

[0115] The focus of the scenario simulation is on modifying the planting density and rotation period. Under the baseline scenario (density of 600 trees / ha)... -1 The rotation period is 20 years, and the simulation time spans from 2006 to 2066, with three rotation periods. The volume of commercially available timber in the year preceding the rotation period enters the forest products module. If rotation is not carried out, the volume of commercially available timber remains at 0, which is consistent with reality, meaning that if no logging occurs, no carbon flows into the forest products carbon pool.

[0116] Referring to the LCA (Life Cycle Assessment) and setting different rotation dates, processing efficiencies, and lifespans, carbon flow paths were simulated. In actual accounting, a strict distinction should be made between the forest carbon pool and the forest product carbon pool, with rotation as the dividing point. In the recycling component, large-diameter and small-diameter timber were allocated, with a ratio of 0.6 for large-diameter timber and 0.4 for small-diameter timber. It was assumed that the recovery rate for large-diameter timber was low (10%) and the recovery rate for small-diameter timber was high (30%). This embodiment also simulated a dynamic recovery rate, increasing by 0.01 annually, with an upper limit set at 0.60, simulating a scenario where the recovery rate increases due to technological advancements and policy influences.

[0117] Taking the baseline scenario as an example, the carbon storage of in-use forest products in this embodiment is as follows: Figure 3 As shown, before the 2026 rotation event, the carbon storage of forest products in Sihong Forest Farm was 0. The 2026 rotation event caused the carbon storage of in-use forest products to peak in 2026. After rotation, due to the use of a first-order decay model, the carbon storage showed an exponential decline, with the paper carbon pool decaying even faster, reflecting the inherent property of paper products accelerating carbon release due to their short service life. The carbon storage of in-use forest products continued to decline until the second rotation event occurred in 2046.

[0118] The cumulative carbon storage of forest products in the use and disposal stages of this embodiment is as follows: Figure 4 As shown, before logging rotation (2007-2025): the carbon stock of timber was 0; during logging rotation (2026): logging caused the carbon pool in use to reach its peak; after logging rotation (2027): logging caused the carbon stock of waste forest products to increase. Figure 5 The study presents the changes in total carbon storage of forest land and forest products and the contributions of each component (biomass carbon, soil carbon, and forest product carbon pool) between 2007 and 2060. It can be seen that while biomass carbon storage decreases in rotation years, forest product carbon storage increases, which is consistent with the flow of carbon pools after rotation.

[0119] The analysis of the carbon budget changes in the target forest land requires calculating the net forestry carbon budget, that is, the net carbon budget at the forest land scale after considering disturbance (logging) factors. In this embodiment, the net forestry carbon budget... The calculation formula is:

[0120]

[0121] In the formula For a specified year Coupled net carbon balance of target forest land; It is the first In this embodiment, the annual net ecosystem productivity of forest land is the [number]th [year] obtained from the TRIPLEX-Management model. Annual change in carbon storage of forest land; This represents the carbon emissions from the waste forest product carbon pool in the forest product carbon storage accounting model. In this embodiment, it is expressed in the form of methane, converted at 28 times the carbon emissions from the CO2 greenhouse effect. The flux is converted to carbon dioxide equivalent units (CO2 equivalent). (in order to compare with the greenhouse gas inventory).

[0122] Figure 6 This paper presents the changes in ecosystem and forest product carbon fluxes obtained in this embodiment. Overall, NBP is positive for most of the period, indicating that the coupled system is a net carbon sink in the long term, while the periodic fluctuations reflect the impact of logging rotation on the ecosystem carbon sink. NBP < NEP, mainly due to methane emissions from forest product waste landfills. After logging rotation, forest products enter waste landfills, generating methane emissions, which lowers NBP. As shown in the figure, logging leads to a short-term carbon source, but remains a net carbon sink in the long term. The average NBP of the forest farm from 2007 to 2060 is 18.5 tCO2e / ha.

[0123] Furthermore, the total value of carbon assets in the target forest land, i.e., forestry carbon pool carbon assets, is calculated using carbon market prices. The formula for measuring carbon assets per unit area is expressed as:

[0124]

[0125] In the formula, Represents carbon assets per unit area; Indicates the first Annual forest biomass carbon pool Indicates the first annual forest soil carbon pool Indicates the first The annual forest product carbon pool, and the above parameters of the carbon pool were all obtained from the simulation process of the coupled model of this invention; This indicates the price of forestry carbon sequestration, which is determined based on annual demand.

[0126] The changes in forestry carbon assets calculated in this embodiment are as follows: Figure 7 As shown, researchers can quantify the forestry carbon sink and carbon storage capacity of forest land and forest products based on the carbon assets of this target forest land. This helps to more accurately predict the impact of different management measures on forest carbon storage and provides more reliable data support for forest management decisions.

Claims

1. A method for assessing forestry carbon sink and carbon storage capacity that couples the entire forest land and forest product industrial chain, characterized in that, include: S1: Collect initial information on the target forest land, set the range of tree species growth parameters, and obtain the input parameters for the process-based ecosystem process model; The ecosystem process model is initialized based on the input parameters, the rotation period is set, forest stand growth is simulated, and the annual forest carbon storage change and forest carbon storage of the target forest land within a specified period are calculated. S2: Construct a forest product carbon storage accounting model based on the IPCC first-order decay method to calculate the forest product carbon storage of the target forest land and the annual change in forest product carbon storage of the target forest land within a specified period. S3: Couple the output of the ecosystem process model with the input of the forest product carbon storage accounting model to obtain a coupled model; the coupled model stores the biomass carbon after each rotation period as forest land carbon storage, and the forest land carbon storage is gradually returned to the atmosphere through the half-life of forest products; S4: Calculate the forestry carbon storage of the target forest land within a specified period using the coupling model, wherein the forestry carbon storage is coupled with the carbon storage of the forest land and the carbon storage of the forest products; analyze the carbon flow path and carbon budget change process of the target forest land, and calculate the carbon assets of the target forest land to assess the forestry carbon sink and carbon storage capacity of the target forest land.

2. The method for assessing forestry carbon sink and carbon storage capacity according to claim 1, characterized in that, The initial information of the target forest land includes meteorological data, soil physicochemical data and vegetation data. The range of tree species growth parameters is set according to expert experience, including stand density, tree height and tree shape.

3. The method for assessing forestry carbon sink and carbon storage capacity according to claim 2, characterized in that, The forest carbon storage includes standing tree biomass and soil organic carbon.

4. The method for assessing forestry carbon sink and carbon storage capacity according to claim 3, characterized in that, The calculation of forest product carbon storage in the target forest land within a specified period includes: According to the method specified by the IPCC, the annual carbon storage of the biomass of the growing forest stand, the annual carbon storage of the in-use forest product carbon pool, and the annual carbon storage of the abandoned forest product carbon pool in the target forest land are calculated separately, and the sum of the three is used to obtain the annual forest product carbon storage.

5. The method for assessing forestry carbon sink and carbon storage capacity according to claim 4, characterized in that, The calculation of the annual forest product carbon storage change of the target forest land includes: Based on the initial forest product carbon storage of the target forest land, the annual forest product carbon storage is accumulated according to the rotation period in the harvesting year to calculate the forest product carbon storage of the target forest land within a specified period; after each harvest, the forest product carbon storage includes the forest product carbon storage that has not been completely degraded before and the forest product carbon storage obtained in this harvest; the difference between the annual forest product carbon storage of two adjacent years is used to obtain the change in forest product carbon storage.

6. The method for assessing forestry carbon sink and carbon storage capacity according to claim 5, characterized in that, The carbon flow pathways of the target forest land analyzed include: The commercially available timber volume output from the ecosystem process model is used as forest land carbon storage, and is allocated to solid forest products and paper forest products in the forest product carbon storage accounting model according to a certain proportion. Several simulation scenarios were set up, each including the corresponding planting density and rotation period; carbon flow paths were simulated with reference to the LCA life cycle assessment.

7. The forestry carbon sequestration capacity assessment method according to claim 6, characterized in that, The analysis of the carbon budget changes in the target forest land includes: The carbon budget of the target forest land is based on a specified year. The forestry net carbon balance is obtained from the coupled forest land-forest product net carbon balance obtained from the coupled model, and is expressed as: In the formula For a specified year Forestry net carbon balance, The first result obtained from the ecosystem process model Annual change in carbon storage. The carbon emissions from the waste forest product carbon pool in the forest product carbon storage accounting model are estimated in the form of methane.

8. The forestry carbon sequestration capacity assessment method according to claim 7, characterized in that, The carbon asset calculation includes: Convert flux to carbon dioxide equivalent units , will specify the year Carbon market prices and forestry net carbon balance Multiplying these values ​​yields the carbon asset value of the target forest land.

9. A forestry carbon sequestration capacity assessment system that couples a process model with carbon budget, characterized in that, include: The data initialization module is used to collect initial information about the target forest, set the range of tree species growth parameters, and obtain the input parameters for the process-based ecosystem process model. The ecosystem process model is initialized based on the input parameters, and the rotation period is set. Ecosystem process models are used to simulate stand growth and calculate the annual changes in forest carbon storage and the forest carbon storage of the target forest over a specified period. The forest product carbon storage accounting model is constructed based on the IPCC first-order decay method and is used to calculate the annual change in forest product carbon storage of the target forest land and the forest product carbon storage of the target forest land within a specified period. The coupling module is used to couple the output of the ecosystem process model with the input of the forest product carbon storage accounting model to obtain a coupled model. The coupled model stores the biomass carbon after each rotation period as forest land carbon storage, and the forest land carbon storage is gradually returned to the atmosphere through the half-life of forest products. The analysis module is used to calculate the forestry carbon storage of the target forest land within a specified period using the coupled model, wherein the forestry carbon storage is coupled with the carbon storage of the forest land and the carbon storage of the forest products; analyze the carbon flow path and carbon budget change process of the target forest land, and perform carbon asset calculation on the target forest land to assess the forestry carbon sink and carbon storage capacity of the target forest land.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of any of the methods described in claims 1 to 8.

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